(a) Field of the Invention
The present invention generally relates to a robotic endoscope for performing inspection and endoscopic procedures, in particular, to a self-propelled tubular robot and an autonomous pipe robot capable of advancing within an elongated passage, either a straight or bent passage, having a rigid or elastic, tubular wall.
(b) Description of the Prior Art
Endoscopes are useful medical device for inspecting and examining the interior of certain human organs that are otherwise inaccessible to a physician's examination. An endoscopic examination, like colonoscopy, is a procedures requiring very demanding techniques. It is a medical art to coax an almost two metres long flexible tube around a tortuous colon whilst causing minimal discomfort and yet performing a thorough examination.
Most experienced endoscopists use similar endoscopic techniques. Air is pumped into the colon to distend it and aid insertion of the flexible tube. The insertion force on the device must be gentle to avoid stretching the colonic wall or mesentery which can cause pain or perforation to the wall. The colonoscope is advanced, by the pushing action of the endoscopist's hand, to the caecum under direct endoscopic vision made available to the endoscopists by optical fibres or CCD cameras. The lumen should be kept always in view so that little or none of the operation is performed blind. A variety of "in-and-out" manoeuvres are used to "accordion" the colon on the colonoscope, keeping the colonoscope as free of loops as possible. However, pushing is not the only action involved. Considerable skill is required to pull, wriggle and shake the colonoscope at the distal end. The patient's abdomen may be pressed to minimize looping and discomfort. In a difficult colon, special manoeuvres (like reducing the "alpha loop" in the sigmoid colon) are used to pass the sharply angulated sigmoid/descending colon junction. Torquing of the colonoscope is also required in such a scenario.
The detailed examination of the mucosa is performed both as the colonoscope is introduced and when it is slowly removed from the caecum. If the colonoscope is kept free of loops, the tip responds well and the examination is facilitated. This is especially true if a therapeutic procedure (such as polypectomy) is to be undertaken, because large, redundant loops of the colonoscope can make control of the tip very difficult. Sometimes, the endoscopist may "jiggle" the scope to pleat the colon onto the shaft of scope. This involves rapid up/down or side-to-side movements of the scope. The main purpose of jiggling is to shorten the part of the insertion tube which is in the body. This keeps it straight.
The basic act of manoeuvring the colonoscopic tip around the many bends of the colon requires years of practice and training. During the operation, the lumen may disappear from the surgeon's sight leading to a "red-out" when the tip is against the colonic wall or worse; a "white-out" when the tip stretches the colonic wall. When this happens, an inexperienced endoscopist may be disorientated and has difficulty looking for the lumen. Colonic perforation may consequently occur. Furthermore, abrupt movements of the scope may result in tearing of the inner wall of the colon, which may in turn lead to excessive bleeding. There are also instances when pushing in the scope does not result in advancement of the distal end. Rather, loops are formed which may result in over distension of the colonic walls. The present colonoscope also requires the endoscopist to hold the control device with one hand leaving only one hand to push or pull the insertion tube. Too much torquing of the insertion tube may result in loops which may complicate matters further. Besides being cumbersome, holding up the control device for prolonged periods of time is tiring for the endoscopist.
The colonoscopy procedure depends very much on the skills of the endoscopist. A more experienced endoscopist will perform a more thorough, less painful operation in a shorter time than an inexperienced endoscopist. A skilled endoscopist will normally have little problems traversing the colonoscope right up to the caecum of a "normal" colon. However, there will be difficulties advancing the colonoscope through some "problematic" colons. This happens when encountering very acute or fixed bends. Further pushing of the colonoscope at this point will only distend the walls of the distal colon. Distortion of the colonic shape and profile due to previous surgery may add to this problem. A self-propelled robotic endoscope with a traversing mechanism at its distal end will solve many locomotion problems unlike the problematic pushing format of conventional colonoscopes.
In the chemical and oil industries, conducting characterization and inspection activities within piping systems is critical to decontamination, dismantlement and maintenance activities. Current technologies for inspection of large piping systems exist. However, the ability to accurately characterize and inspect small-diameter piping systems are rare. Small-diameter pipes (diameters less than 3 inches) are generally connected together to form 3-dimensional structures made up of horizontal and vertical pipes. Inspecting of such piping systems would require a self-propelled in-pipe robot not only capable of advancing against gravity but also capable of traversing through acute bends. The robot's objective is to send back images of the inner walls of the pipes as it advances into the pipes. It must also be able to proceed in a desired direction when it reaches a junction with two or more alternative routes.